1. Field of the Invention
The present invention relates to a suction recovery device which is applicable to a printer, a copying machine, facsimile terminal equipment, a typewriter, and a word processor that are generally used as business machines, or an ink jet recording apparatus comprising complex equipment. This invention is also especially effective for an electronic typewriter having a word processing feature.
2. Related Background Art
A conventional arrangement of an absorbing member disposed within a cap is typically disclosed in U.S. Pat. No. 4,600,931. With this arrangement, a recording head is protected from drying out due to the heat insulating effect of the cap, because the ink absorbing member, impregnated with ink, is disposed within the cap which caps the recording head. Another arrangement in which an absorbing member is contained within a cap is known in U.S. Pat. No. 4,543,589.
Further, a capping device used in an ink jet recording apparatus is disclosed in British Laid-Open Patent Application No. 2,184,066, which discloses an ink suction port provided on a lower portion within a cap, and an ink absorbing member partially contained within the cap so as to entirely close the ink suction port therein.
Recently, however, recording time has increased, because ornamental characters or graphics are frequently recorded, for example, by a word processor. During such a long recording, the capping of the recording head may be often omitted. Moreover, the present inventor has found the following new problems from an investigation of these recording conditions.
As an ink absorbing member disposed within a cap is subject to the atmosphere for a long time, it often occurs that the ink absorbed in the ink absorbing member becomes dry. This drying may cause some amount of an additive contained in the ink, such as color or pigment, to stick to the absorbing member due to the evaporation of water or alcohol in the ink. Thus a new problem occurs that the gas permeability of the ink absorbing member deteriorates, thereby reducing the absorbing capability of the absorbing member.
The present inventor also examined another main method of ink recovery using a predischarge (which is described in detail in GB2169855), wherein the use of an idle suction (which is described in detail in U.S. Pat. No. 4,558,332) to suck and remove the ink makes the device more complex, resulting in the need for higher power consumption, or the need for a larger pumping power due to the increased volume of the absorbing member. The present inventor has developed this invention as a result of carrying out various experiments to enhance the ink retention capability of an ink absorbing member as much as possible.